Collector streets for industrial subdivisions shall be planned to serve industrial areas exclusively and shall connect with arterial streets so that no industrial traffic shall be directed into any residential streets. The intersections of service streets from parking areas with arterial or collector streets shall not be less than 150 feet from the intersection of the arterial or collector street with any other street. Streets shall be planned to be extended to the boundaries of any adjoining land planned for industry, except for severe physical conditions or if the Planning Commission finds such extension is not in accord with the approved plan of the area.